Sure, ...
Kid=: 1 2,_ 1,:_ _
Key=: 94 48 92
Red=: 0 1 1
N=: 4
clean=: 3 :0
b=. (#y) > +/y e."1,9!:6''
}.}:b #inv b# |:y
)
dbg=: 4 :0
echo clean^:2 ":x;('#',":#$y);('$',":$y);'';y
)
safeshow=: 3 : 0
assert. 0 < N=:N-1
1 dbg z=. ''
assert. 1=#$z
'l r'=. y{Kid
if. l<#Kid do.
2 dbg z=. '(',(safeshow l),') '
assert. 1=#$z
end.
3 dbg z=. z,(":y{Key),':','BR'{~y{Red
assert. 1=#$z
if. r<#Kid do.
4 dbg z=. z,' (',(safeshow r),')'
assert. 1=#$z
end.EMPTY
)
safeshow 0
1 #1 $0
1 #1 $0
3 #1 $4 48:R
1 #1 $0
3 #1 $4 48:R
|assertion failure: safeshow
After every assignment, z has a rank of 1,
None of the assignments are from the result of safeshow.
This suggests that cutting back the stack is implemented in an
inconsistent fashion -- at least some of the time it may complete
execution of the "current line" but despite that it leaves the code in
a state which suggests that that "current line" has yet to be
executed.
Thanks,
--
Raul
On Wed, Jun 15, 2022 at 2:49 PM Henry Rich <[email protected]> wrote:
>
> Since I don't have a machine, I can't verify that anything is wrong. You
> are failing in the third execution of show, using values that derive from
> echo & might have rank 2. Why don't you type out the value of z at each
> recursion?
>
> Henry Rich
>
> On Wed, Jun 15, 2022, 6:53 PM Raul Miller <[email protected]> wrote:
>
> > That missing final z would not be ok for 'safeshow' to function properly.
> >
> > But the problem here is not "how should 'safeshow' be changed to
> > function properly?" -- the problem here is "how do we use the debugger
> > to help us understand how J functions?" or perhaps "what is wrong with
> > the debugger? / how do we get the debugger to work properly? / how do
> > we understand J?"
> >
> > Specifically, why is z rank 1 for assert and echo when the computed
> > result was rank 2?
> >
> > Thanks,
> >
> > --
> > Raul
> >
> > On Wed, Jun 15, 2022 at 1:49 PM Henry Rich <[email protected]> wrote:
> > >
> > > I am away from my machine, but I observe that the result of safeshow
> > comes
> > > from echo, not z. Is that ok?
> > >
> > > Henry Rich
> > >
> > > On Wed, Jun 15, 2022, 7:03 AM Raul Miller <[email protected]> wrote:
> > >
> > > > I am running into a problem, in J903 and J904 -- I haven't yet
> > > > installed earlier versions of J on this machine.
> > > >
> > > > safeshow=: 3 :0
> > > > assert. 0 < N=:N-1
> > > > z=. ''
> > > > assert. 1=#$z
> > > > echo #$z
> > > > 'l r'=. y{Kid
> > > > if. l<#Kid do.
> > > > z=. '(',(safeshow l),') '
> > > > assert. 1=#$z
> > > > echo #$z
> > > > end.
> > > > z=. z,(":y{Key),':','BR'{~y{Red
> > > > assert. 1=#$z
> > > > echo #$z
> > > > if. r<#Kid do.
> > > > z=. z,' (',(safeshow r),')'
> > > > assert. 1=#$z
> > > > echo #$z
> > > > end.
> > > > )
> > > >
> > > > Kid=: 1 2,_ 1,:_ _
> > > > Key=: 94 48 92
> > > > Red=: 0 1 1
> > > > N=: 3
> > > > safeshow 0
> > > > 1
> > > > 1
> > > > 1
> > > > |assertion failure: safeshow
> > > >
> > > > Now, there's a problem here with my data which triggers the assertion
> > > > -- Kid should not contain any duplicate values other than _. But
> > > > that's not what I am concerned with here.
> > > >
> > > > In Jqt, I enable debugging (control-K) and when the debugger pops up
> > > > on the assert, I go back to the previous stack frame, and I find that
> > > > z has rank 2, instead of rank 1.
> > > >
> > > > Specifically, it has the value '48:R',' (',:' '
> > > >
> > > > So, now I am trying to figure out what's gone wrong.
> > > >
> > > > Conceptually, I could accept that z was being modified by virtual
> > > > block handling -- except there's no update to z which would have given
> > > > it a rank 2 value.
> > > >
> > > > Another possibility here is that there's something specifically wrong
> > > > with my machine. So: can anyone else reproduce this issue?
> > > >
> > > > And, ... the next most likely possibility is that there's something
> > > > wrong with the J engine itself.
> > > >
> > > > Anyways, I'd like to get someone else's perspective here.
> > > >
> > > > Thanks,
> > > >
> > > > --
> > > > Raul
> > > > ----------------------------------------------------------------------
> > > > For information about J forums see http://www.jsoftware.com/forums.htm
> > > >
> > > ----------------------------------------------------------------------
> > > For information about J forums see http://www.jsoftware.com/forums.htm
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
